I got a nice surprise this morning. I have had a tank inside the house that had no heating or lighting and was experimenting with plant growth using this method. At the time I threw in a couple of cheap red cherries and I also put in a female rifle shrimp I had.  I used pool filter sand as the substrate and I used a slow release aquagrow fertiliser tablet in under each of the plants. I have litrally done nothing else with it and thought I had lost all the shrimp over the two odd years it has been setup.  I recently added a heater after deciding to utilise this tank again for shrimp. I added a few red gene blue rilli and when I looked into the corner of the tank and found the female rifle. She is about 3cm long. Maybe I need to get her a boyfriend.

 The pictures are not the best

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Edited June 12, 201510 yr by Callan

Riffles are one of the toughest shrimp available in the hobby.

 

At 3 cm, its certainly in the range that riffles transition to being female, but may yet be male! 

Oh really I thought the males stayed smaller but thanks for the info I wasn't aware of that. Is there a way of telling males and females? He/She would be at least 2 1/2 years old.

I need to read up what triggers the change (if it is even known!). The males change sex to females at around an inch (2.5cm) in size. However I'm sure there is a bit of wriggle room around this size. From an evolutionary point of view, it may be an advantage to stay a large male because you can outcompete the other (smaller) males to the females. At the same time, changing to a female at a smaller size is going to be evolutionary advantageous if there are lots of other males around. Point is, I don't believe that the shrimp hit an exact size (or even age) and turn into females. Instead I think it is highly variable.

Definitely if the shrimp is below 2cm or greater than 3.5-4cm they are male or female respectively. It might be possible to sex the shrimp based on external characteristics but since size is usually a good indicator of sex (except in the 'transition' size range), I've never bothered.

Sex change is dependent on several factors and size at which this change occurs can be variable. Check pleopods 1 and 2 to find out if the shrimp is male, female or in between.

What features on the pleopods would be evident for males or females? Is it similar to freshwater crayfish in that the males and females have different positions for the openings to the sexual organs? 

Have a look at the David Preston's thesis 2009. Southern Cross Uni.

Have a look at the David Preston's thesis 2009. Southern Cross Uni.

Funnily enough, I ordered a copy of this thesis last night. Also ordered a copy of Smiths PhD thesis (1987) from JCU on riffle shrimp ecology. Shame neither published anything. 

Do you think there might be enough interest in a seminar or workshop for forum members on the taxonomy and ecology of atyid or other shrimps or crustacean? I am happy to run these free of charge. Somewhere central like northern NSW or SEQld?

uluru would be more central !

I would certainly be interested.

It might be easier to do a webinar or video, giving a basic rundown on how its all done. You could also get forum members to ask questions beforehand for you to address during the presentation. 

+1 webinar

I found that face to face and hands on to be more useful. Nothing like looking at the body parts under the microscope and seeing the variations. Would include looking at the chromatophores (cells containing the colour pigments) and how they move to effect colour change. Can use a local school or uni bio lab. Some people may be willing to travel. ...

Well if you are doing a practical class, I'm there. I believe more people would be willing to travel for a practical class than to see a lecture or two. 

I would be keen too

Where would you suggest for the first one? I'm not sure how spread the SKF members are. I could repeat it elsewhere if there's enough interest.

We are pretty spread out, basically all over Aus. Might be easiest in one of the eastern capital cities - Sydney, Brisbane or Melbourne.

I would love to see this happen in Melbourne and I'd like to think that Shrimp Club Vic could host it at a meeting. What do you think Lodo? 

Sounds pretty interesting. If you want, pm me details about what you think would be good? Could propose it to the scv group. That would be if your happy to travel. But yes, pm is probably best for discussion on coming to Vic. Also we could attempt a live stream if it were to happen

Hmmmm we could do in brissie and podcast it as well.

Brissy needs a club ;) what a good way to have a first meeting :p

Brissy needs a club ;) what a good way to have a first meeting :p

http://shrimpkeepersforum.com/forum/topic/9379-shrimp-keepers-club-brisbane/?do=getNewComment 

I happy to do it in Melbourne, Sydney and Brisbane. Just need to know when, in order to fit them into my travel timetable.

That sounds fantastic ura! Please PM lodo regarding the scv timetable and potential meeting dates. Thanks! 

I can do one in Brisbane any date in July and until mid August.